This invention relates to a character erasing mechanism of a printing apparatus, and more particularly to a character erasing mechanism for erasing printed characters including an underline.
Generally, character erasable electronic typewriters and other printing apparatus are furnished with an automatic correction mechanism for erasing wrong printed characters by erasure key operation. Such automatic correction mechanism erases characters by the cover-lap method by adhering a correction fluid on the wrong printed characters, or the lift-off method for lifting off the printed ink by a correction ribbon, and recently the lift-off method is generally employed.
In this lift-off method which is designed to erase the wrong printed character by peeling off the ink printed on the printing paper by means of a correction ribbon, it is desired that the printing element be located in the same position when printing and when erasing. That is, if the position of the printing element at the time of erasing is deviated from that at the time of printing, a certain portion of the printed ink is not peeled off. To erase the wrong printed character completely, it is desired that the printing element be exactly on the same location when printing and when erasing. However, a complicated and expensive mechanism is required to attain such positional accuracy.
Conventionally, therefore, for example in the Japanese Patent Publication (examined) No. 56-46992 (this application corresponds to U.S. Pat. No. 4,307,971) and Japanese Patent Publication (non-examined) No. 60-147376, in the printing apparatus applying the lift-off method, it was proposed to peel off the ink of a wrong printed character completely by repeating the erasing action while moving the carriage slightly right and left.
In such conventional printing apparatus, when an underlined character is printed in the automatic underline mode, the underline can be erased at the same time when the underlined character is erased by the automatic correction function.
At this time, the printing apparatus, as stated above, erases the wrong printed character by moving the carriage slightly right and left, and it also moves the carriage right and left when erasing an underline, and the wrong printed character can be completely erased, but the underline is erased more than the erased character portion by the extent of moving the carriage slightly. As a result, as shown in FIG. 12, after erasure, when a correct underlined character (a character H) is printed, the underline 80 has a gap 81 corresponding to the extent of moving the carriage slightly so as to be discontinuous, and a beautiful underline printing consecutive with the preceding and succeeding underlines cannot be achieved.